Won’t run on all cylinders

[Foxy1057]

Hi everyone , just joined and need advice please?
I have recently bought a79 z1000st American import.
Although somebody has spent a lot of money restoring the bike it just won’t run right ! It won’t fire on all of the cylinders all of the time ,and it’s not always the same cylinder that has a colder header pipe . Everyone I speak to says it’s your pilot jets ? Having looked in the tank it does seem quite rusty even though there is a inline fuel filter on the fuel pipe ? I have been advise to re seal the tank before I do anything else , just wondered what you guys thought on this are ?

[Philippe]

Hi Foxy1057

welcome to the club!
You've bought the correct bike, the Z1000ST is my favorite too.
It's a shame it doesn't run right. The only thing you can do to correct it is start all over again.
Find a Kawasaki shop repair manual or download one.
Clean the fuel tank, make sure there's no more rust. Don't forget to clean the fuel tap!
Take the carbs off, separate them, disassemble them and clean them ultra sonic.
Buy new carb rebuild kits, assemble the carbs, get the fuel levels correct, synchronise the carbs and mount them back.
If that doesn't solve the problem you'll have to look at the ignition.
If you don't have the skills to do this yourself, find a good mechanic, someone who knows the old bikes and how to repair them.
Good luck!
Oh, before I forget, show us some pictures of your bike please, come on, don't be shy.
Greetings from Belgium.
Philippe

[Garry.L]

Hi everyone , just joined and need advice please?
I have recently bought a79 z1000st American import.
Although somebody has spent a lot of money restoring the bike it just won’t run right ! It won’t fire on all of the cylinders all of the time ,and it’s not always the same cylinder that has a colder header pipe . Everyone I speak to says it’s your pilot jets ? Having looked in the tank it does seem quite rusty even though there is a inline fuel filter on the fuel pipe ? I have been advise to re seal the tank before I do anything else , just wondered what you guys thought on this are ?

Could be the Pilots. Worth noting it's not always just the Pilot Jets that get blocked but the actual pilot circuits (pathways) inside the carbs, and sometimes even an ultrasonic clean won't always clean them out.

[Stugill]

I appreciate that carbs are a PITA to set up etc and when I had issues I also assumed it was carbs.

I then checked the spark on whichever downpipe/cylinder that wasn't getting hot and found no spark or weak spark. I also had the irritating 'moving about' issue and my coils were playing up intermittently. I changed to Dyna coils, with Dyna S and all good.

You never know.

Good luck

Stu

[Foxy1057]

Thanks guys for all your feed back , I have ordered some pet seal for the tank , then I’m going to look at removing the carbs and see what I find!!!

[Foxy1057]

Does anybody know what the accelerator pump does on carb no2 ? Apparently on US models z1000st , when I look at carb rebuild kits it says not suitable for these carbs ??

[warren3200gt]

Don't have any bikes with pumper carbs but as I understand it they squirt a bit of fuel into the carb throat if you wack open the throttle quickly. On standard carbs if you wack open the throttle the butterfly/slide will open and create a lean mixture until the fuel system catches up.
Not somthing I've ever noticed as a problem on my bike with standard carbs so would probably delete the pumper Circuit on any bike I had which had them.

[zed1015]

Does anybody know what the accelerator pump does on carb no2 ? Apparently on US models z1000st , when I look at carb rebuild kits it says not suitable for these carbs ??

The 28mm pumper are the best carbs of the bunch.
You can buy the diaphragms and other parts from NRP Manchester ( Google them ).
You should only need to replace o'rings, gaskets, Float valves and choke plunger seals.
Unless broken the original brass should be retained.
If any need replacing only use Genuine Mikuni or Keyster parts.
Never use cheap ebay or chinese rubuild kits, they are garbage and cause more issues than they solve.

[Foxy1057]

Hi all , brief update
I have taken the carbs off and cleaned the idle jets and main jets and blown them through ! I have pet sealed the tank , but can’t put any fuel in for seven days , so I have started the bike with a funnel connected to the fuel line , it started but was coughing and back firing even with flames coming out the exhaust!!
Anybody any ideas of what is causing this? I’ve hit a brick wall

[Foxy1057]

Another thought !
If the low tension connections to the coils were the wrong way round would this cause the back firing etc ??

[warren3200gt]

Sure would. Easy to check just swop em back over or swop the ht leads if long enough.

[zed1015]

Another thought !
If the low tension connections to the coils were the wrong way round would this cause the back firing etc ??

If you got the LT leads mixed up it would maybe backfire etc but it wouldn't run at all so that's not your issue.
Intermittent spark/fueling /overfueling on a cylinder or two or ign timing is the more likely cause or maybe the bike just need a good run to clear it out and settle things.

[Foxy1057]

Well just swapped the wires on the coil that does 2and 3 because it looked that it was wrong according to a wiring diagram and now I have no spark on these cylinders at all ! Tried a new coil on that side and still nothing ! Would I have blown a fuse? It’s firing on 1&4 still

[warren3200gt]

Just re read your previous post and Rob is correct it wouldn't have run if the coil trigger wires were reversed it would certainly have back fired out the exhaust which is what I replied too.
2&3 & 1&4 both have the same power feed so not a blown fuse. Check your connections to that coil from ignition plate to coil and also that it is getting power.

[Foxy1057]

Hi warren
I swapped the two wires on the same coil not coil to coil does that make a difference ? Now that I have swapped them back there is no spark from that coil ?